This application claims the priority of German patent document 10 2004 026 711.1, filed May 28, 2004 (PCT International Application No. PCT/DE2005/000885, filed May 14, 2005), the disclosures of which are expressly incorporated by reference herein.
The present invention relates to an electronic component for use in aircraft and to a flight sensor for such components, as well as a method of controlling electronic components on board aircraft.
On board an aircraft, for safety reasons it must be ensured that electromagnetic waves do not interfere with the aircraft's systems. All electronic components intended for installation in aircraft therefore require a special permit to assure that they do not emit interfering radio waves or electromagnetic waves and thereby impair the safety of the aircraft operation. This special permit can be granted only if it is established that the component emits no interfering or safety-impairing radio waves during the flight.
Such approval procedures, however are very costly, and fault sources may occur despite the high-expenditure approval procedure.
One object of the present invention, therefore, is to increase the safety for the use of electronic components in aircraft.
Another object of the invention is to permit a simpler approval of components emitting radio waves.
These and other objects and advantages are achieved by the flight sensor according to the present invention, which is suitable particularly for use in aircraft, and which comprises a vibration sensor for converting structure-borne sound to electric vibration signals. A filtering device receives the vibrations signals, for determining the fraction thereof that is attributable to engine sounds of the aircraft relative to the overall sound in the vibration signals, and a comparator compares the engine sounds with the overall sound and generates a flight status signal from the result. The flight status signal represents a defined flight status of the aircraft.
The flight sensor according to the invention enhances safety on board aircraft. By generating the flight status signals, electronic components can be correspondingly controlled, so that it is ensured that the respective component cannot transmit during the flight. The invention permits electronic components equipped with the flight sensor according to the invention to independently recognize in a reliable manner whether they are situated in aircraft that is flying, or one that is not. The flight sensor according to the invention therefore cost-effectively and reliably prevents electronic components for use in aircraft from transmitting interfering radio signals. Furthermore, the flight sensor can be implemented in a very small construction, so that it is particularly suitable also as a standardized safety element for electronic components for use in aircraft. This further increases safety and simplifies the authorization procedure for the electronic components.
The flight status signal emitted by the comparator preferably contains information concerning the “flight” or “no flight” as a flight status. On the basis of these two possibilities of the flight status signal, an electronic component can be prevented (or not prevented) from transmitting radio waves.
Particularly on the basis of a decision between only two possible situations, the flight sensor provides a very high degree of safety, while it can be connected with electronic components for use in aircraft in a cost-effective and simple manner.
The filtering device advantageously comprises a low-frequency filter which is designed for the frequency range of the engine sounds. As a result, the engine sounds can be detected in a simple and reliable fashion by means of standard components, so that a cost-effective implementation can be carried out.
The filtering device advantageously comprises a broad-band threshold value filter for generating a comparator threshold. As a result, a suitable threshold for the comparator can be generated from all sound signals so that the “flight” or “no flight” status can be detected particularly well, and reliably. In particular, the filtering device preferably comprises at least one RMS converter for converting filter signals to effective values, particularly to proportional direct voltages.
Advantageously, the filtering device comprises a low-frequency channel for determining the fraction of sounds attributable to the engine and a threshold value channel connected parallel to the low-frequency channel for generating a comparator threshold. As a result, the comparator can reliably compare the engine sound with the overall sound and thereby make a decision concerning flight or no flight.
The low-frequency channel preferably comprises a low-frequency filter with a first RMS converter connected on the output side. The reaction time of the flight sensor is an important quantity which is determined in or by the RMS converter of the low-frequency channel. A low reaction time occurs as a result of the special development.
The threshold value channel preferably comprises a threshold value filter having a second RMS converter connected to the output side.
Advantageously, the comparator is connected to the output side of the filtering device and generates a digital output signal as the flight status signal. As a result, the output signal of the comparator is cost-effective and easy to use, and simple interfaces to the corresponding electronic components can also be created.
According to one aspect of the invention, a method of controlling electronic components on board an aircraft comprises the following steps: Detecting structure-borne sound on-board an aircraft; determining the fraction of such engine sound which is attributable to the engine, generating a flight status signal as a function of the engine sound fraction, the flight status signal representing a “flight” or “no flight” status; and controlling an electronic component by means of the flight status signal such that an emission of interfering electromagnetic waves is prevented during flight.
The control method according to the invention enhances aircraft safety, and simplifies and accelerates the authorization process for electronic components.
Engine sound is preferably compared with the entire detected sound and a decision is made with respect to the “flight” or “no flight” status based on the comparison, providing a simple and reliable technique for preventing the emission of interfering electromagnetic waves of electronic components as a function of the flight status.
The electronic component is advantageously switched off when the flight status signal that the aircraft is in flight, ensuring safety on board aircraft in the case of those components which are not required in the flight operation, or must be switched-off.
According to another aspect of the invention, an electronic component is provided for use in aircraft, which electronic component comprises a flight sensor according to the invention as described here.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.